// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_COMPILER_ZONE_STATS_H_
#define V8_COMPILER_ZONE_STATS_H_

#include <map>
#include <set>
#include <vector>

#include "src/globals.h"
#include "src/zone/zone.h"

namespace v8 {
namespace internal {
    namespace compiler {

        class V8_EXPORT_PRIVATE ZoneStats final {
        public:
            class Scope final {
            public:
                explicit Scope(ZoneStats* zone_stats, const char* zone_name)
                    : zone_name_(zone_name)
                    , zone_stats_(zone_stats)
                    , zone_(nullptr)
                {
                }
                ~Scope() { Destroy(); }

                Zone* zone()
                {
                    if (zone_ == nullptr)
                        zone_ = zone_stats_->NewEmptyZone(zone_name_);
                    return zone_;
                }
                void Destroy()
                {
                    if (zone_ != nullptr)
                        zone_stats_->ReturnZone(zone_);
                    zone_ = nullptr;
                }

            private:
                const char* zone_name_;
                ZoneStats* const zone_stats_;
                Zone* zone_;
                DISALLOW_COPY_AND_ASSIGN(Scope);
            };

            class V8_EXPORT_PRIVATE StatsScope final {
            public:
                explicit StatsScope(ZoneStats* zone_stats);
                ~StatsScope();

                size_t GetMaxAllocatedBytes();
                size_t GetCurrentAllocatedBytes();
                size_t GetTotalAllocatedBytes();

            private:
                friend class ZoneStats;
                void ZoneReturned(Zone* zone);

                using InitialValues = std::map<Zone*, size_t>;

                ZoneStats* const zone_stats_;
                InitialValues initial_values_;
                size_t total_allocated_bytes_at_start_;
                size_t max_allocated_bytes_;

                DISALLOW_COPY_AND_ASSIGN(StatsScope);
            };

            explicit ZoneStats(AccountingAllocator* allocator);
            ~ZoneStats();

            size_t GetMaxAllocatedBytes() const;
            size_t GetTotalAllocatedBytes() const;
            size_t GetCurrentAllocatedBytes() const;

        private:
            Zone* NewEmptyZone(const char* zone_name);
            void ReturnZone(Zone* zone);

            static const size_t kMaxUnusedSize = 3;
            using Zones = std::vector<Zone*>;
            using Stats = std::vector<StatsScope*>;

            Zones zones_;
            Stats stats_;
            size_t max_allocated_bytes_;
            size_t total_deleted_bytes_;
            AccountingAllocator* allocator_;

            DISALLOW_COPY_AND_ASSIGN(ZoneStats);
        };

    } // namespace compiler
} // namespace internal
} // namespace v8

#endif // V8_COMPILER_ZONE_STATS_H_
